Heatpipes are heat transfer equipment, which transfers heat from a hot fluid to a cold fluid, and involve two way change of phase from liquid to gas and back to liquid.
I like to share this What is Heat Transfer with you all through my article.
Principle of Heat Pipes
The principle of the heat pipe can be explained with a simple design of heat pipe as described below.
Theheat pipe has an evacuated hollow tube with a non-toxic fluid like water or any other coolant inside as shown in the diagram below. The coolant used will depend on the temperatures of the fluid to be cooled.
Theliquid coolant is at the lower portion of the tube and it collects heatfrom the hot fluid outside the tube. The hot fluid and the coolant do not come into contact with each other but the heat transfer takes place through the tube walls. This region of the heat pipe is called the evaporating section. The liquid coolant vaporizes absorbing heat from the hot fluid through the pipe walls and rises to the top of the tube.
The tube is maintained at a low pressure close to the vapor pressure of the coolant so that the coolant vaporizes at a lower temperature. The hot vapors are cooled at the top of the tube by releasing heat to the environment or to other cooling media and this section is called the condensing section. The vapor condenses and flows down by gravity and the cycle is repeated. The rate of condensation of the vapor is a major factor determining the rate of heat transfer
Theabove design is simplified for the sake of understanding and there are several substantially different and complicated designs for the heat pipes for various requirements. There are also designs for heat pipes, which can be used for heating and cooling fluids as required
Advantages and Uses of Heat pipes
Heatpipes are compact static units with no moving parts and require no mechanical maintenance. They offer lower pressure drop saving fuel consumption and higher heat recovery. Heat pipes can be designed to operate across various ranges of temperatures and offer
Heatpipes find wide use not only in day-to-day appliances like air conditioners, PCs, Laptops etc but also in higher engineering applications like boilers, dryers for paint and paper and even in high technology areas like cryogenics in space technology.